and one such device was called the salters duck named after its inventor stephen salter from edinburgh. the duck was tested waves but never on the open sea. eventually these ideas fell by the wayside. in the early 2000 came a new attempt with this snake like offshore device its link cylindrical sections flex and bend in the waves and convert the motion into electricity but it never got past the prototype stage. german engineers are currently testing another system the ne most project involves flotation modules connected to pulleys on the seabed by flexible cables as they're pulled by the motion of the waves a generator transforms the mechanical energy into electricity it's being tested as an addition to offshore wind farms. so far most of the approaches to topping marine power have got nowhere one reason the formidable technical hurdles. wave heights change continually constant the force of the waves to stand up to the biggest waves the machinery has to be very robust but this equipment produces too little energy. when waves are gentler there are many different ways of harnessing wave